If Ramon can mow the entire lawn in x -3 hours, then how much of the lawn does he mow per hour?
Toxic pollutants. The annual cost in dollars for removing p% of the toxic chemicals from a town's water supply is given by the formula C(p) =500, 000/100-p
a) Use the accompanying graph to estimate the cost for removing 90% and 95% of the toxic chemicals.
b) Use the formula to find C(99.5) and C(99.9).
c) What happens to the cost as the percentage of pollutants removed approaches 100%?
Magazine sales. Henry sold 120 magazine subscriptions in x days.
a) Write a rational expression for the rate at which he sold the subscriptions.
b) Suppose that he continues to sell at the same rate for 5 more days. Write a rational expression for the number of magazines sold in those 5 days.
If Ramon can mow the entire lawn in x -3 hours, then
how much of the lawn does he mow per hour?
Ramon can mow the whole lawn (100% of it) in x - 3 hours. We want to know how much he can mow in 1 hour. Let's call this amount "y". We can set up an equation:
100 percent y percent
-------------- = --------------
(x - 3) hours 1 hour
We want to solve for y:
100/(x - 3) = y/1
100/(x - 3) = y
So, in one hour, Ramon can mow 100/(x - 3) percent ...